n, q = list(map(int, input().split()))
mod = 371036193751
S = [ord(s)-96 for s in input()]
for _ in range(q):
    Q = list(map(str, input().split()))
    if Q[0] == "1":
        S[int(Q[1])-1] = ord(Q[2])-96
    else:
        T = Q[1]
        x = 0
        for t in T:
            x = (x*30+ord(t)-96)%mod
        le = len(T)
        pe = pow(30, le, mod)
        t = 0
        f = 0
        for i in range(n):
            t = (t*30+S[i])%mod
            if le <= i:
                t = (t-pe*S[i-le])%mod
            if t == x:
                f = 1
        print("Yes" if f else "No")